the rear does not need any extra kind of reinforcement from the shock mounts, it wont make any significant difference. the front strut bar, however, is a very good mod and you will feel a nice improvement in stability and less body roll. Un-hinged bars work the best, but hinged is better than no brace at all.
i agree with MrM3. i just recently installed the e46 M3 strut brace on mine. i can feel the difference when cornering. my brace may not be the best brace out there, but it was the only one that i liked. you will have no regrets to do this mod.
i really don't see a need for the rear brace, but if you want it, then go for it.